The add-on has a built-in cache which caches the SalesForce.com API calls. For more details on the cache implementation and how to fine-tune it, please refer to the data caching knowledge base article.

You can further reduce the calls by using broader search queries and then filtering them down using the {xxx-filter} macros (part of Reporting plugin) to filter down the result set.

Likewise, you can also do your sorting using {xxx-sort} macros (part of Reporting plugin) to sort your results.